16309 has 4 divisors (see below), whose sum is σ = 16704. Its totient is φ = 15916.

The previous prime is 16301. The next prime is 16319. The reversal of 16309 is 90361.

16309 is nontrivially palindromic in base 7.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90361 = 109 ⋅829.

It is a cyclic number.

It is not a de Polignac number, because 16309 - 2³ = 16301 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

16309 is a lucky number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127 + ... + 220.

It is an arithmetic number, because the mean of its divisors is an integer number (4176).

2¹⁶³⁰⁹ is an apocalyptic number.

It is an amenable number.

16309 is a deficient number, since it is larger than the sum of its proper divisors (395).

16309 is an equidigital number, since it uses as much as digits as its factorization.

16309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394.

The product of its (nonzero) digits is 162, while the sum is 19.

The square root of 16309 is about 127.7066952043. The cubic root of 16309 is about 25.3596026368.

Subtracting from 16309 its sum of digits (19), we obtain a triangular number (16290 = T₁₈₀).

Adding to 16309 its product of nonzero digits (162), we get a triangular number (16471 = T₁₈₁).

It can be divided in two parts, 16 and 309, that added together give a triangular number (325 = T₂₅).

The spelling of 16309 in words is "sixteen thousand, three hundred nine".